In recent years, a tape stop detecting mechanism has been developed in which the detecting mechanism performs the detection operation by detecting stoppage in the rotation of a tape reel rest on which is mounted a tape reel. In conventional tape stop detecting mechanisms, two rotary members and a lever are provided. The first rotary member is frictionally engaged with the tape reel rest and the second rotary member has both a cam portion and an engagement portion. The first rotary member rotates or stops with the tape reel rest whereas the second rotary member rotates continuously. The lever is arranged to be urged in one direction by the cam portion of the second rotary member into a position where the lever is able to engage with engagement portion of the second rotary member.
However, the lever is simultaneously urged in another direction by the first rotary member so that the lever may, in fact, be prevented from engaging with the engagement portion of the second rotary member. Furthermore, the conventional tape stop detecting mechanism has a disadvantage in that the tape stop detecting operation may erroneously occur at the time of, for example, the beginning of play back operation. This results from the engagement portion of the second rotary member accidentally engaging the lever before the first rotary member reaches into engagement with the lever, due to a large marginal rotation gap therebetween. The conventional tape stop detecting mechanism has another disadvantage in that it is difficult to manufacture in proper positional arrangement because the positional relationship of the lever relative to both rotary members is very critical in order to accurately perform the tape stop detecting operation and to prevent false detection such as of the beginning of the tape play back.